#include <stdio.h>

int main(int argc, char *argv[]) {

    int a, b, c, d,e;
    scanf("%d %d %d",&a,&b,&c);
    d = c / b;
    e = c % b;
    if (e!=0)
    {
        a = a - (d + 1);
    }else{
        a = a - d;
    };

    printf("%d", a);

    return 0;
}